Transvascular albumin transport and protein replenishment after haemorrhage in the chronically catheterized pregnant rabbit.

Pregnancy is characterized by increases in both blood and interstitial volumes, but the mechanisms are unknown. To test the hypotheses that blood volume (BV) recovery after haemorrhage in pregnant (P) is faster than in nonpregnant (NP) rabbits, and that this can be explained by a higher capillary filtration, a 20% BV haemorrhage was produced in a group of 7 P and 7 NP rabbits. We determined the BV recovery (measured by 99Tc), the total plasma protein mass and the haematocrit at 10, 20, 30, 60 and 1440 min after haemorrhage.

Cardiovascular changes after closure of uterine circulation during pregnancy.

To assess the effects of the presence of the uteroplacental circulation on the systemic arterial pressure, blood volume, and cardiac output during pregnancy, we measured those variables and plasma renin activity (PRA) during a 30-min period before and after occlusion of the uterine circulation. After uterine vascular occlusion, pregnant rabbits (n = 7) experienced a drop in mean arterial pressure of 8.7%, heart rate of 9.